diff options
author | Thomas Voss <mail@thomasvoss.com> | 2024-11-27 20:54:24 +0100 |
---|---|---|
committer | Thomas Voss <mail@thomasvoss.com> | 2024-11-27 20:54:24 +0100 |
commit | 4bfd864f10b68b71482b35c818559068ef8d5797 (patch) | |
tree | e3989f47a7994642eb325063d46e8f08ffa681dc /doc/rfc/rfc2424.txt | |
parent | ea76e11061bda059ae9f9ad130a9895cc85607db (diff) |
doc: Add RFC documents
Diffstat (limited to 'doc/rfc/rfc2424.txt')
-rw-r--r-- | doc/rfc/rfc2424.txt | 227 |
1 files changed, 227 insertions, 0 deletions
diff --git a/doc/rfc/rfc2424.txt b/doc/rfc/rfc2424.txt new file mode 100644 index 0000000..d3daf31 --- /dev/null +++ b/doc/rfc/rfc2424.txt @@ -0,0 +1,227 @@ + + + + + + +Network Working Group G. Vaudreuil +Request for Comments: 2424 Lucent Technologies +Category: Standards Track G. Parsons + Northern Telecom + September 1998 + + + Content Duration + MIME Header Definition + +Status of this Memo + + This document specifies an Internet standards track protocol for the + Internet community, and requests discussion and suggestions for + improvements. Please refer to the current edition of the "Internet + Official Protocol Standards" (STD 1) for the standardization state + and status of this protocol. Distribution of this memo is unlimited. + +Copyright Notice + + Copyright (C) The Internet Society (1998). All Rights Reserved. + +Overview + + This document describes the MIME header Content-Duration that is + intended for use with any timed media content (typically audio/* or + video/*). + +1. Abstract + + This document describes the MIME header Content-Duration that is + intended for use with any time varying media content (typically + audio/* or video/*). The length of time is represented in seconds + without any units indication. + +2. Content-Duration Header Field + + Time varying media contents, for example, a spoken voice message or a + video clip, have an inherent time duration. Many audio and video + encodings may include their duration as header information or may + allow accurate calculation based on the byte length of the data. + However, it may be useful to present the time duration of the content + in a MIME header to allow its simple determination without dealing + with the actual content. + + + + + + + +Vaudreuil & Parsons Standards Track [Page 1] + +RFC 2424 Content-Duration September 1998 + + + The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", + "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this + document are to be interpreted as described in [REQ]. + +2.1 Syntax + + The Content-Duration field's value is a single number specifying the + time duration in seconds of the content. Formally: + + duration := "Content-Duration" ":" 1*10DIGIT + + Note that practically (though highly unlikely in MIME media), the + upper bound on the numerical value of the time duration is (2^^31 - + 1) or 2147483647. + +2.2 Semantics + + This field represents the time duration of the associated time + varying media content. The time duration is noted in seconds with no + units tag. The time value should be exact, however the exact value + of the time duration cannot be known without opening the content and + playing it. If an exact value must be known, then the latter method + should be used. This mechanism simply allows placing a sender + determined time duration value in the header for easy access. + + Though there are several ways to present this duration to the + recipient (e.g. with the inbox headers, when audio attachment + opened), the actual use of this field on reception is a local + implementation issue. + +2.3 Example + + In this example the content duration represents 33 seconds: + + Content-Duration: 33 + +3. VPIM Usage + + The Content-Duration header field for the audio/32KADPCM sub-type is + a useful component of the VPIM specification [VPIM2]. All VPIM + Messages MUST contain this sub-type to carry the audio of a voice + message. It may be useful in some instances (e.g. viewing on a + simple MIME or non-MIME desktop) to have the time duration of the + voice message available without having to open the audio content. + + + + + + + +Vaudreuil & Parsons Standards Track [Page 2] + +RFC 2424 Content-Duration September 1998 + + +4. Security Considerations + + This definition introduces the option of explicitly identifying the + time duration of an audio/* or video/* content outside of the binary + data that forms the content. In some environments (though likely not + the majority), the identification of the actual time duration in a + header field may be a security issue and as a result should not be + noted. Reliance on the time indicated in this header field cannot be + trusted for the purposes of determining the exact size of the data. + The exact length of the data must be determined by examining the data + itself. + +5. Authors' Addresses + + Glenn W. Parsons + Northern Telecom + P.O. Box 3511, Station C + Ottawa, ON K1Y 4H7 + Canada + + Phone: +1-613-763-7582 + Fax: +1-613-763-4461 + EMail: Glenn.Parsons@Nortel.ca + + + Gregory M. Vaudreuil + Lucent Technologies + 17080 Dallas Parkway + Dallas, TX 75248-1905 + United States + + Phone/Fax: +1-972-733-2722 + EMail: GregV@Lucent.Com + +6. References + + [MIME2] Freed, N., and N. Borenstein, "Multipurpose Internet Mail + Extensions (MIME) Part Two: Media Types", RFC 2046, November + 1996. + + [VPIM2] Vaudreuil, G., and G. Parsons, "Voice Profile for Internet + Mail - version 2", RFC 2421, September 1998. + + [REQ] Bradner, S., "Key words for use in RFCs to Indicate Requirement + Levels", BCP 14, RFC 2119, March 1997. + + + + + + +Vaudreuil & Parsons Standards Track [Page 3] + +RFC 2424 Content-Duration September 1998 + + +7. Full Copyright Statement + + Copyright (C) The Internet Society (1998). All Rights Reserved. + + This document and translations of it may be copied and furnished to + others, and derivative works that comment on or otherwise explain it + or assist in its implementation may be prepared, copied, published + and distributed, in whole or in part, without restriction of any + kind, provided that the above copyright notice and this paragraph are + included on all such copies and derivative works. However, this + document itself may not be modified in any way, such as by removing + the copyright notice or references to the Internet Society or other + Internet organizations, except as needed for the purpose of + developing Internet standards in which case the procedures for + copyrights defined in the Internet Standards process must be + followed, or as required to translate it into languages other than + English. + + The limited permissions granted above are perpetual and will not be + revoked by the Internet Society or its successors or assigns. + + This document and the information contained herein is provided on an + "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING + TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING + BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION + HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF + MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. + + + + + + + + + + + + + + + + + + + + + + + + +Vaudreuil & Parsons Standards Track [Page 4] + |